Low Voltage On One Phase

[proximity]

I have a rented house with a 15(45) three phase meter. I came home tonight to find that probably one phase, or maybe two were very low voltage. Some lights were noticeably dimmer, water pump output severely reduced, and some air-conditioning units would not start. In addition, some street lighting in the moo baan was out. Some lighting and air-conditioners were normal. After about one hour all the lighting went back to normal and everything worked again. I didn't see the PEA come out and change anything near the transformer.

What could case this to happen? If it happens again is there anything I should check on my end? Also can low voltage damage anything? I wanted to turn off the laboring water-pump but when I opened the consumer unit I found 8 unlabeled circuit breakers.

Edited April 6, 2010 by proximity

[Naam]

"Also can low voltage damage anything?"

yes it can. i spent a fortune replacing burned out starting relays on aircons and pumps till i installed a device (expensive!) which shuts down a phase completely in case of low voltage.